Author(s): Xiongdong Zhou; Mengzhen Xu
Linked Author(s): Xiongdong Zhou, Mengzhen Xu
Keywords: No Keywords
Abstract: The Bai River is a typical meandering river lying on the Zoige wetland, China. As a result of its fluvial process, numerous oxbow lakes have been formed and scattered on the floodplain, which modified the landscape and provided unique habitats for the aquatic fauna and flora. In this study, we investigated the ecological statuses of different types of habitats in the Bai River basin using macroinvertebrates as indicators. Four main types of habitats were identified, and the differences of environmental conditions, macroinvertebrate assemblages and trophic levels among them were statistically compared. The substrate size and the macrophyte biomass were found, through the redundancy analysis (RDA), to be two important factors influencing the macroinvertebrate assemblages. Two Lasso regression models were further established to describe the relationships that how macroinvertebrate density and macrophyte biomass responded to environmental variables and hydrological connectivity, respectively. Our results showed that, the oxbows were characterized by significantly high levels of dissolved oxygen and pH, but low levels of total nitrogen and nitrate. Luxuriant submerged macrophyte covers found in these oxbows were responsible for the more autotrophic conditions, which supported significantly more abundant macroinvertebrates comparing to their river origins. Macroinvertebrate diversities in the Bai River basin were found the highest in the oxbows with the lowest hydrological connectivity to the adjoining rivers, which was essentially the result of the presence and luxuriance of submerged macrophytes.
Year: 2018